Prunus tree rootstock named ‘Piku 1’

ABSTRACT

A new and distinct Prunus rootstock compatible with other Prunus varieties and producing trees with reduced growth, hardiness to frost and high productivity.

Classification: Prunus L.

Varietal denomination: ‘Piku 1’.

BACKGROUND OF THE INVENTION

The present invention comprises a new and distinct cultivar of hybridPrunus known by the varietal name ‘Piku 1’. The new variety wasdiscovered in 1972 in a selective breeding program designed to producegrowth reducing rootstock for cherry trees in Dresden-Pillnitz, Germanyas a cross between an unnamed, unpatented variety of Prunus aviumrootstock seedling (female parent) and an unnamed, unpatented Prunushybrid of Prunus canescens×Prunus tomentosa (male parent). The newvariety differs from its parents in its growth habit. The followingcharacteristic distinguish the new variety from Prunus avium rootstockvarieties:

1. Three-way hybrid.

2. Reduces growth in grafted varieties by 30%.

3. Precocious, about 1-3 years.

4. Higher productivity.

5. Propagated by green cuttings or tissue culture.

6. High resistance to winter frost.

7. Leaf margins roll inwards.

The new variety was first asexually reproduced via green cuttings andtissue culture in 1975 in Dresden-Pillnitz, Germany and subsequentpropagation therein has confirmed that the characteristics of the newvariety are stable and are transmitted to subsequent generations.

DESCRIPTION OF THE DRAWINGS

The accompanying photographic drawings illustrate the new variety, withthe color being as nearly true as is possible with color illustrationsof this type.

FIG. 1 shows the tree of the new variety;

FIG. 2 shows a branch with leaves;

FIG. 3 shows a branch with flower buds; and

FIG. 4 shows a branch with opened flowers.

DESCRIPTION OF THE PLANT

The following detailed description sets forth the characteristics of thenew cultivar. The data which defines these characteristics werecollected by asexual reproductions via green cuttings and tissue culturecarried out in Dresden-Pillnitz, Germany. The color designations weretaken in outdoors Dresden-Pillnitz, Germany. Rootstocks were 6 to 7years old when described. Color designations are noted with reference tostandard P. avium rootstock. The new variety is adaptable to soil and isfree of PNRV and PDV. As a rootstock, it can be reproduced via softwoodcuttings and tissue culture. The new variety anchors well with few rootsprouts, good compatibility with grafts and exhibits reduced growth.

TREE

Size: Medium; having an average height of 2.60 m and an average width of1.90 m.

Form: Upright, broad.

Trunk:

Surface texture.—Exfoliating.

Bark color.—Middle brown to dark brown.

Diameter.—7.0 cm, measured at a height of 40 cm.

Branches:

Surface texture.—Smooth.

Bark color.—166A to 200B; similar to a birch tree.

New growth color.—Light-dark red.

Mature growth color.—Dark brown.

Average crotch angle.—45-50°.

Internode length.—About 1.8 cm.

Lenticels.—Diameter: 0.05-0.15 cm. Color: 160D. Amount per shoot: >100.

Bud.—Small.

Leaves:

Length.—9.1 cm.

Width.—4.0 cm.

Surface texture.—Fine, smooth.

Form.—Elongated, elliptical.

Color.—Upper Surface: 146A. Lower Surface: 146B.

Margin.—Rolls towards upper surface.

Petioles:

Length.—1.4 cm.

Thickness.—0.12 cm.

Leaf glands:

Quantity.—1-2.

Position.—On the end of the leaves.

Size.—0.15 cm.

Color.—Red-brown.

Stipules:

Quantity.—Rare.

Length.—1.0-1.5 cm.

Flowers:

Diameter.—2.50 cm.

Color.—Upper Surface: N155A. Lower Surface: N155A.

Number.—Many.

Petals.—Length: Approximately 1.2 cm. Width: Approximately 0.6 cm.Quantity per flower: 5.

Sexual characteristics.—Diploid.

Stamen number.—>10.

Pistil number.—1.

FRUIT

Maturity date/location: Early in Dresden, Pillnitz.

Size: Small; low crop yield.

Weight: 1-2 grams.

Axial diameter: 1-1.5 cm.

Fruit stone:

Length.—0.7 cm.

Diameter.—0.4 cm.

Skin: Thin, soft, colored 187A.

Flesh color: 187A.

Seeds: Surface color 159C/159D, having a smooth texture.

GENERAL

Weather hardiness: Tolerant to winter frost.

Disease resistance: Tolerant to Cytospora.

I claim:
 1. A new and distinct variety of Prunus rootstock named ‘Piku1’ substantially as shown and described.